Monthly variation in the proximate composition of jack mackerel ( Trachurus japonicus ) from Geumo Island, Korea

Proximate analysis for proportions of lipids, proteins, ash, and water contents of fish tissue provides a powerful insight to obtain physiological information for the fish population being studied. In this study, the proximate compositions for the jack mackerel ( Trachurus japonicus ) caught in Geumo Island, Korea known as a nursery ground were examined monthly in 2013 and 2014. No significant seasonal variation was found in protein and ash contents whereas a strong seasonal variation was found in water and lipid contents. The lipid contents showed relatively higher values ranging from 3.94% to 5.75% in summer and fall which corresponds to their active feeding periods. A strong inverse relationship was found between the lipid and water contents (n = 16, r = −0.859, p t -test, p